AC resistance bridge based on the cryogenic current comparator

Author

Seppa, H. ; Satrapinski, A.

Author_Institution

VTT Autom. Meas. Technol., Espoo, Finland

fYear

1996

fDate

17-21 June 1996

Firstpage

402

Lastpage

403

Abstract

This paper describes a low-frequency AC resistance bridge based on a Cryogenic Current Comparator (CCC). A low-noise dc SQUID is used as a null detector. The bridge is the main tool to trace resistance to 10 k/spl Omega/, 100 /spl Omega/ and 1 /spl Omega/ levels from the quantum Hall resistance (QHR). The ratio of the resistors ranging from 1 /spl Omega/ to 10 k/spl Omega/ can be measured with an uncertainty of the order of 1 ppb. The bridge is typically operated with a PC generating a sinusoidal ac signal ranging from 0.1 Hz-2 Hz. Using a vector analyzer as a signal source the bridge is used up to 1 kHz. Both sinusoidal and pseudorandom signals have been used to verify the frequency dependence of the standard resistors against the QHR. At present, the bridge can be used to perform accurate calibrations only up to 10 Hz.

Keywords

SQUIDs; bridge circuits; bridge instruments; calibration; cryogenic electronics; current comparators; electric resistance measurement; measurement standards; quantum Hall effect; 0.1 to 10 Hz; 1 ohm to 10 kohm; accurate calibrations; cryogenic current comparator; frequency dependence; low-frequency AC resistance bridge; low-noise dc SQUID; null detector; pseudorandom signals; quantum Hall resistance; resistor ratio; sinusoidal ac signal; sinusoidal signals; standard resistors; vector analyzer; AC generators; Bridges; Cryogenics; Detectors; Electrical resistance measurement; Measurement uncertainty; Resistors; SQUIDs; Signal analysis; Signal generators;

fLanguage

English

Publisher

ieee

Conference_Titel

Precision Electromagnetic Measurements Digest, 1996 Conference on

Conference_Location

Braunschweig, Germany

Print_ISBN

0-7803-3376-4

Type

conf

DOI

10.1109/CPEM.1996.547135

Filename

547135